Filters can be employed in a variety of applications. In some instances, channel filters are appropriate for channel selectivity and anti-aliasing before analog-to-digital (A/D) conversion. For 60 GHz communication systems, channel bandwidth is on the order of 1 GHz. Future 60 GHz standards will likely use channel bonding with channel bandwidth far in excess of 1 GHz.
U.S. Patent Publication 2009/0278625 discloses a broadband filter filtering noise over a first conductive wire, a second conductive wire, and a third conductive wire, which includes a differential-mode filtering circuit connected to both the first conductive wire and the second conductive wire and a common-mode filtering circuit connected to both the first conductive wire and the second conductive wire. The differential-mode filtering circuit includes two inductors and two capacitors for filtering differential-mode noise of different frequencies. The common-mode filtering circuit includes two inductors and six capacitors filtering common-mode noise of different frequencies.
U.S. Patent Publication 2010/0022215 discloses baseband filters for use in wireless communication devices. An embodiment of a baseband filter in a transmitter subsystem of a wireless device comprises an operational amplifier (op-amp), a pole circuit, a feedback capacitor, and an active device. The op-amp is adapted to produce an amplified signal that includes noise gain produced by the op-amp. The pole circuit is electrically coupled with an output terminal of the op-amp, and is adapted to receive the amplified signal and to attenuate the noise gain to produce a filtered, amplified signal. The feedback capacitor is electrically coupled between the first pole circuit and an input terminal of the op-amp, and is adapted to compensate for a phase shift produced by the pole circuit. The active device is electrically coupled with the pole circuit, and is adapted to amplify the filtered, amplified signal and to produce a baseband filtered output signal.
U.S. Patent Publication 2007/0008030 discloses a control system for programmable filters.